根據JS中的選定項值從對象數組中查找項

Question

我有一個這樣的數組：

var array = [
    { name:"string123", value:"this", other: "that" },
    { name:"string2", value:"this", other: "that" },
    { name:"string12", value:"ths", other: "that" },
];

現在我有一個像'string12'這樣的字符串。 現在有了這個字符串 output 我想要的是找到包含這個字符串的項目，就像：

var array = [
    { name:"string123", value:"this", other: "that" },
    { name:"string12", value:"ths", other: "that" },
];

這是我嘗試過的：

 const search = (nameKey, myArray) => { for (var i = 0; i < myArray.length; i++) { var newArr = []; if (myArray[i].name.slice(0, nameKey.length + 1) === nameKey) { newArr.push(myArray[i]); } return newArr; } } var array = [ { name:"string123", value:"this", other: "that" }, { name:"string2", value:"this", other: "that" }, { name:"string12", value:"ths", other: "that" }, ]; var resultObject = search("string12", array); console.log(resultObject);

但我的解決方案是返回一個空白數組。 我哪里錯了？

Answer 1

您的實施中出現以下問題：

1. 將初始化移到for循環之外。
2. 執行.slice()時不需要 +1。
3. return 語句return newArr應該在for循環之外。

const search = (nameKey, myArray) => {
    var newArr = [];
  
  for (var i = 0; i < myArray.length; i++) {
    if (myArray[i].name.slice(0, nameKey.length) === nameKey) {
      newArr.push(myArray[i]);
    }
  }
    return newArr;
}

var array = [
  { name:"string123", value:"this", other: "that" },
  { name:"string2", value:"this", other: "that" },
  { name:"string12", value:"ths", other: "that" },
];

var resultObject = search("string12", array);
console.log(resultObject);

Answer 2

使用Array#filter和String#includes ：

 const arr = [ { name:"string123", value:"this", other: "that" }, { name:"string2", value:"this", other: "that" }, { name:"string12", value:"ths", other: "that" } ]; const res = arr.filter(({ name }) => name.includes('string12')); console.log(res);

如果您只需要檢查名稱是否以字符串開頭，則可以使用String#startsWith而不是includes 。

Answer 3

您可以使用Array.filter和startsWith function ( docs ) 來執行此操作。 如果您想在name中的任何位置檢查string12 ，請使用includes而不是startsWith

 var array = [ { name:"string123", value:"this", other: "that" }, { name:"string2", value:"this", other: "that" }, { name:"string12", value:"ths", other: "that" }, ]; const filtered = array.filter(item => item.name.startsWith("string12")); console.log(filtered);

Answer 4

如果您只是在開始時搜索字符串，那么從myArray[i].name.slice(0,nameKey.length + 1) 中刪除 + 1將對您有用，那么只有它會匹配您正在搜索的確切字符串並且您還必須在循環上方聲明 newArr 以便它可以保存該值並在循環結束后返回它希望它有幫助

    const search = (nameKey, myArray)=> {
    var newArr = [];
    for (var i=0; i < myArray.length; i++) {
        if (myArray[i].name.slice(0,nameKey.length) === nameKey) {
            newArr.push(myArray[i]);
        }
    }
    return newArr;
}

var array = [
    { name:"string123", value:"this", other: "that" },
    { name:"string2", value:"this", other: "that" },
    { name:"string12", value:"ths", other: "that" },
    { name:"string1234567", value:"ths", other: "that" },
];

var resultObject = search("string12", array);
console.log(resultObject);

你也可以使用現代語法來解決這個問題

const search = (nameKey, myArray) => {
  return myArray.filter(elem => elem.name.startsWith(nameKey));
};

var array = [
  { name: "string123", value: "this", other: "that" },
  { name: "string2", value: "this", other: "that" },
  { name: "string12", value: "ths", other: "that" },
];

var resultObject = search("string12", array);
console.log(resultObject);